This invention relates to an electronic component cooling apparatus for cooling an electronic component such as an MPU or the like, and more particularly to an electronic component cooling apparatus of the type that a heat sink on which an electronic component is mounted is forcibly cooled by air fed from a fan unit.
An electronic component cooling apparatus of the type that a heat sink including a plurality of radiation fins and a fan unit are combined with each other has been conventionally known in the art, as disclosed in Japanese Patent Application Laid-Open Publication No. 268125/1994, Japanese Patent Application Laid-Open Publication No. 83873/1996, U.S. Pat. No. 5,519,574, U.S. Pat. No. 5,484,013, U.S. Pat. No. 5,452,181, U.S. Pat. No. 5,421,402, U.S. Pat. No. 5,251,101 and U.S. Pat. No. 5,309,983 and the like.
An electronic component cooling apparatus disclosed in Japanese Patent Application Laid-Open Publication No. 268125/1994 or U.S. Pat. No. 5,309,983 is so constructed that air sucked by a fan unit is forcibly fed to a heat sink. Also, in the electronic component cooling apparatus disclosed, air discharged from blades of the fan unit being rotated about a revolving shaft of a motor is forcibly fed in a radial direction of the revolving shaft rather than an axial direction thereof, to thereby increase cooling efficiency of the electronic component cooling apparatus.
The conventional electronic component cooling apparatus is typically constructed in such a manner that air which is discharged from the fan unit to absorb heat of the radiation fins, resulting in being heated is guided in all directions from a whole circumference of the heat sink. In this respect, an electronic component cooling apparatus disclosed in U.S. Pat. No. 5,309,983 or U.S. Pat. No. 5,519,574 and more specifically FIG. 3A of the patent includes a heat sink having a plurality of radiation fins arranged thereon in a manner to be spaced from each other at intervals while being kept parallel to each other, resulting in air being discharged in two directions in which the radiation fins extend.
Also, U.S. Pat. No. 4,513,812 discloses an electronic component cooling apparatus which is so constructed that an electronic component which generates heat is arranged on a front surface of an elongated base. The base is provided on the front surface thereof with a plurality of radiation fins extending in a longitudinal direction of the base. The cooling apparatus also includes a fan unit which includes a cover member having a wall arranged opposite to the base and is mounted on the base. In the electronic component cooling apparatus thus constructed, air flow forcibly guided from the fan unit toward the base is discharged through two openings provided on both ends of the base defined in a longitudinal direction thereof. Unfortunately, the cooling apparatus disclosed has a disadvantage that the heat sink is significantly increased in size due to arrangement of both electronic component and radiation fins on the base.
Japanese Utility Model Publication No. 23034/1990 discloses an electronic component cooling apparatus including a heat sink which includes a plurality of radiation fins and is arranged on an elongated base and a fan unit which includes a cover member arranged opposite to the base. The radiation fins are arranged so as to permit air fed from the fan unit to be guided in at least one of a width direction of the base perpendicular to a longitudinal direction thereof and an oblique direction between the longitudinal direction and the width direction. Thus, the cooling apparatus permits air to be discharged either in all directions of the elongated base or in a width direction thereof.
U.S. Pat. No. 5,615,998 discloses an electronic component cooling apparatus which is provided with an engagement structure including a plurality of fitting sections provided at a fan unit and a plurality of fitted sections provided at a heat sink and engaged with the fitting sections. The fitting sections and fitted sections are permitted to be engaged with each other by merely approaching the fan unit to the heat sink. Also, the engagement structure of the apparatus includes two engagement members which permit engagement between the fitting sections and the fitted sections to be released when force is applied to ends of the engagement members by two fingers.
An electronic appliance such as a microcomputer or the like in which such an electronic component cooling apparatus is used has been extensively reduced in size, resulting in a space defined around the electronic component cooling apparatus being reduced correspondingly. Thus, when the electronic component cooling apparatus is constructed so as to discharge heated air in all directions from a whole circumference of the heat sink, there occurs a problem that a temperature of other electronic components arranged around the electronic component cooling apparatus is caused to be increased to a level exceeding an allowable level. In particular, the problem is amplified with an increase in length of the heat sink.
The problem has been conventionally solved only by discharging air heated by the heat sink on both sides defined in the longitudinal direction of the heat sink. Unfortunately, such restriction in direction of discharge of the air causes another disadvantage of reducing cooling efficiency of the electronic component cooling apparatus.